In multilayer photographic elements used for color photography there are usually three selectively-sensitized emulsion layers coated on one side of a photographic support. For example, the uppermost layer is generally blue sensitive, the next layer generally comprises a yellow filter and the next layer is generally green sensitive. The emulsion layer adjacent to the support is generally red sensitive. The yellow filter layer located between the blue and green sensitive layers serves to absorb the blue radiation which may be transmitted through the blue-sensitive layer to the underlying layers which are sensitive to the blue region of the spectrum in addition to the red or green regions of the spectrum. Some of these multilayer photographic elements contain additional silver halide emulsion layers for specialized purposes. In photographic print material, frequently the yellow filter layer is omitted and the arrangement of silver halide emulsion layers may be changed for the purpose of obtaining more accurate recording of the color image.
Photographic elements of the type employed in the present invention are typically subjected to a reversal color process in which the exposed material is given a conventional black-and-white negative development, followed by a reversal re-exposure or exposures and finally color development. Usually, phenolic or naphtholic couplers are used to produce the cyan dye, open chain di-.beta.-ketone couplers are generally used for producing yellow dye images and 2-pyrazolin-5-one couplers generally are used to produce the magenta dye images. In the development step, the dye image is produced by contacting the reversal exposed silver halide with an aqueous alkaline developer solution containing a primary aromatic amino color developing agent in the presence of the appropriate color-forming coupler.
In the processing of photographic color materials by a reversal technique in which the color-forming couplers are incorporated in the color developers, it is well known to use a balancing developing agent in one or more of the color developers. This practice is particularly common with respect to the cyan color developer, but may also be employed in the magenta color developer and the yellow color developer. Such balancing developing agents generally serve two functions; first, such balancing developing agents act as antioxidants and they frequently react with oxidized color developers through a cross-oxidation reaction which regenerates the desired color developing agents; secondly, such balancing developing agents react directly with the exposed silver halide as an auxiliary developing agent. The desired effect of using such balancing developing agents is to improve the photographic quality, for example, to decrease high light stain and/or improve the sensitometric curve shape for the developed dye image.
A particularly valuable class of diffusible couplers for use in yellow-dye-forming developing compositions are the haloacetanilide couplers described in Ross, U.S. Pat. No. 3,929,484, issued Dec. 30, 1975. These couplers are particularly advantageous in photographic processing in that they exhibit excellent solubility properties and excellent color-forming efficiency. Primary aromatic amino color developing agents which are especially advantageously utilized in yellow-dye-forming developing compositions containing the aforesaid haloacetanilide couplers are the N-alkyl-N-alkoxyalkyl-p-phenylenediamines of Bent et al, U.S. Pat. No. 3,658,525 issued Apr. 25, 1972.
To increase the rate of color development and the maximum density of the dye image, it is well known to incorporate a 3-pyrazolidinone balancing developing agent in a color developing composition containing a primary aromatic amino color developing agent and a diffusible coupler (see, for example, Canadian Pat. No. 731,087 issued Mar. 29, 1966). Heretofore, the compound 1-phenyl-3-pyrazolidinone has been used as a balancing developing agent in a yellow-dye-forming developing composition of the type described above; specifically a composition in which the haloacetanilide coupler is alpha-pivalyl-alpha-(4-carboxyphenoxy)-2,4-dichloroacetanilide and the N-alkyl-N-alkoxyalkyl-p-phenylenediamine developing agent is 4-amino-N-ethyl-N-(2-methoxyethyl)-m-toluidine di-p-toluene sulfonate. While such yellow-dye-forming developing composition has enjoyed extensive commercial use and generally exhibits excellent characteristics, an improvement in its stability would be highly advantageous to minimize loss in yellow D-max.
It is toward the objective of providing an improved yellow-dye-forming developing composition of significantly increased stability that the present invention is directed.